Preparation of hybrid fluorescent–magnetic nanoparticles for application to cellular imaging by self-assembly

A unique fluorescent–magnetic hybrid bimodal nanocomposite was prepared by the layer-by-layer self-assembly (LbL) technique fabrication of water-soluble conjugated polymers (CPs) onto the CoFe2O4@SiO2 core–shell nanoparticles (NPs). First, magnetic CoFe2O4 nanoparticles were prepared as the magnetic core and coated with a SiO2 shell to obtain a good dispersion in aqueous solution. Then the polyelectrolytes and cationic conjugated polymer PFV was assembled onto the surface of core–shell nanoparticles by the LbL technique. The prepared nanocomposites were magnetically responsive and fluorescent, simultaneously. Finally, the biomacromolecule heparin sodium (HS) was then assembled on the outer layer of the nanocomposite to provide a cytocompatible surface. The nanocomposites show monodispersity, good fluorescence and good biocompatibility that are useful for efficient cellular imaging. Moreover, the colloidal stability and the cellular uptake ability of the nanocomposition with HS layer were efficiently improved.